1. Brief Description of the Invention
The instant invention relates to a novel method of in vivo diagnosis of upper gastrointestinal diseases.
2. Brief Description of the Prior Art
Factors adversely affecting the function of the gastrointestinal system in humans are exceedingly varied in their nature. Such disorders may arise in the upper or lower gastrointestinal tracts, or both. There is a broad range of causes of gastrointestinal disorders, including genetic, physiological, environmental and psychogenic factors. Accordingly, the diagnosis and management of these disorders can be exceptionally difficult.
Among the chronic disorders of the upper gastrointestinal tract are those which fall under the general categories of gastritis and peptic ulcer disease. The upper gastrointestinal tract is generally defined as including the esophagus, the stomach, the duodenum, the jejunum and ileum. Peptic ulcers are lesions of the gastrointestinal tract lining, characterized by loss of tissue due to the action of digestive acids and pepsin. It has generally been held that peptic ulcers are caused by gastric hypersecretion, decreased resistance of the gastric lining to digestive acids and pepsin, or both. Gastritis is, by definition, an inflammation of the stomach mucosa. In practice, though, the disorder is manifested by a broad range of poorly-defined, and heretofore inadequately treated, symptoms such as indigestion, "heart burn", dyspepsia, and excessive eructation.
As with the management of any disorder, the rapid, precise, and accurate diagnosis of gastrointestinal disorders is of paramount importance. The typical means used to diagnose the gastrointestinal disorder presented by a given patient will depend upon such factors as the nature and severity of symptoms, the overall health of the individual, the medical history of the patient, the need for a specific diagnosis in order to implement a treatment with reasonable likelihood of success, and the availability of diagnostic devices. However, the diagnostic methods typically employed in the art are often slow, cumbersome, costly, and may yield equivocal or inaccurate results. Thus, for patients not having severe symptoms, a precise diagnosis of a gastrointestinal disorder might not be attempted. Such patients may simply be treated with conventional therapies, such as with antacids or drugs which inhibit stomach acid secretion. While such therapies might provide temporary symptomatic relief, a cure is often not effected. More effective treatments may depend upon better diagnoses of the actual underlying gastrointestinal disorder. In particular, it has been discovered that many such gastrointestinal disorders are mediated by infection of gastric mucosa by Helicobacter pylori. H. pylori is a Gram-negative spiral organism which produces the enzyme urease. The organism is predominantly found beneath the mucus layer of the luminal aspect of the gastric epithelium and in the gastric pits. Helicobacter can be diagnosed by blood test for antibodies, breath test, or biopsy of the stomach lining. Antibodies, however, can remain positive for many months after the bacteria have been eradicated. The presence of antibodies presents a falsely positive result in approximately 10 to 15% of patients. Biopsies are relatively quick; however, they add time, expense and risk. Although relatively minor, there is a 1 in 20,000 risk of bleeding from a biopsy site. Biopsies cannot be performed on patients who have a tendency to bleed, such as patients with hemophilia and liver disease. Additionally, it has recently been found that Helicobacter is patchy, thereby requiring multiple biopsies to obtain 100% accuracy. The cost for a biopsy is approximately $100. Biopsies also increase the risk of the person handling the tissue being exposed to HIV. If a urease test is used, the biopsy sample must be placed in the test by the nurse, thereby requiring an additional person during the test.
The prior art has disclosed testing for gastrointestinal disorders, the majority of which have been in vitro. Many tests have also been disclosed using urea and indicators.
Marshall, 4,748,113 discloses compositions and methods for the diagnosis of gastrointestinal disorders involving urease. Methods include obtaining a gastric sample material and contacting the material with a composition including urease and an indicator.
Marshall 4,830,010, discloses methods for the diagnosis of gastrointestinal disorders. The method steps include administration of urea-containing compositions prior to assay.
Steward et al, 5,139,934 disclose substrate compositions and method of urease assay. The method is an in vitro immunoassay that includes the use of pH indicators.
Nagatsu et al, 4,147,692 disclose methods and compositions for measuring enzymatic activities and correlating such activities with various disease states.
Kraffczyk et al, 3,873,369 disclose calorimetric indicators for the determination of urea.
Vasquez et al, 4,851,209 disclose in vivo diagnostic procedures for the clinical evaluation of gastrointestinal ulcer disease using radioactive isotopes. Procedures involve prior administration of a diagnostic pharmaceutical followed by scintigraphic imaging of the gastrointestinal area of interest with scintigraphic imaging equipment.
Although the use of urease or other indicators has been used in combination with pH indicators, all except Vasquez et al are conducted in vitro.
The instant invention discloses a method of detecting the alkaline pH change in vivo. The test dramatically cuts down the number of biopsies required and is safe for patients having any bleeding tendencies while being rapid and low cost. Additionally, through the color change, it can be determined if the change is a true positive or a false positive reaction.